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Estimating Poison Exposures Not Reported to U.S. Poison Centers

On average, almost 6000 poison exposures are reported to U.S. poison centers each day. But how many poison exposures are not reported? That's a challenging question to answer because there is no explicit case by case comparison of reported versus unreported poison exposures across all poison exposure types or treatment sites. However, comparison with a number of other data sets give us insight into the percentage of poison exposures that are reported to U.S. poison centers:

In 2004, the Institute of Medicine1 estimated "more than 4 million poisoning episodes (actual or suspected poisonings) occur in the United States annually". But U.S. poison centers reported only 2,395,582 human poison exposures in 2003 (the latest data year available to the IOM), thus the IOM data suggest that more than 40.1% of U.S. human poison exposures were not reported to poison centers.

In 2015, the Centers for Disease Control and Prevention (CDC) analyzed emergency department visits for drug poisoning in the U.S. from 2008-2011, finding an average of 1.1 million visits each year.2 The National Poison Data System (NPDS; current name of the database for all cases reported to U.S. poison centers) was queried for comparable 2011 data on drug poisonings reported to U.S. poison centers and managed in a healthcare facility (possibly overestimating NPDS cases). That comparison found that 59.5% of ED visits for drug poisonings were not reported to U.S. poison centers.

In 2000, Hoppe-Roberts3 compared poisoning fatalities reported to the National Center for Health Statistics with those reported to the Toxic Exposure Surveillance System (the former name of the database for all cases reported to U.S. poison centers). Using 1994 data, the authors found that 95.4% of fatal poisoning cases were not reported to U.S. poison centers.

In 2016, a National Center for Health Statistics vital statistics summary of 2014 U.S. fatality data identified 51,966 poisoning deaths.4 The National Poison Data System reported only 1559 (directly reported) poisoning deaths in 2014. Thus 97.0% of unintentional poisoning deaths were not reported to U.S. poison centers.

Since only 1 to 2% of poison exposures are fatal, we chose to use the data in the first two studies above, focusing on the comparison of all poison exposures (study 1) and emergency department visits for poison exposures (study 2), excluding the comparison of reported and unreported fatalities (studies 3 and 4). Using the data from studies 1 and 2, between 40.1% and 59.5% of poison exposures are never reported to poison centers. Since 6,000 cases/day are reported to poison centers, the data suggest that another 4,000 to 9,000 poison exposures cases are not reported to poison centers each day. That finding is especially worrisome because it suggests that some people just guess what to do in a poison emergency, risking serious outcomes because of incorrect triage or incorrect treatment recommendations, for example failing to seek urgent healthcare when it is indicated. Others may seek unnecessary emergency health care when it is not needed, increasing the cost and inconvenience of treating poison exposures. For whatever reason, every day some 4,000 to 9,000 people in the U.S. are opting not to see expert guidance from Poison Control when faced with a poison exposure, risking serious injury and placing an unnecessary burden on our health care system.